By which process is a fragment of $DNA$ transferred into a bacterial host cell?

Which of the following is used for direct gene transfer?

Assertion : Insertion of recombinant $DNA$ within the coding sequence of $\beta -$ galactosidase results in colourless colonies.
Reason : Presence of insert results in inactivation of enzyme $\beta -$ galactosidase known as insertional inactivation.

Pure $DNA$ precipitated by the addition of chilled ethanol can be removed from the solution by

Downstream processing includes:
$I.$ Separation of the product from the reactor
$II.$ Purification of the product
$III.$ Formulation of the product with suitable preservatives
$IV.$ Quality control testing and clinical trials in case of drugs
Which of the statements given above are correct?

What should be the constant temperature maintained for the inoculum (in $^oC$)?